Trenches & Holes


top and lower trench. Drone photo courtesy of Legor Productions

updated 20170712

note: if you click on any image it will expand so you can view close up

Recently we partook in a project creating large trenches on a couple of properties.

Jesus suggested the idea, and directed us. He was going to do some large holes filled with matter at his place and Pete and I decided we would really like to do the same at our place. We also wanted help out in the process at Jesus & Mary’s to gain some valuable training and make use of the earth moving equipment in the area.

We felt it was a great opportunity to get the project started, learn about project management, execution, following direction and a whole heap of other stuff.

Here’s the break down of the process for your information.

Why the Project Was Done (including but not limited to…):

  • To benefit the land by retaining water to slowly seep down hill from the trenches and holes. This re-hydrates the land. The more water you can keep in & on the land rather than having it all run off, the better it is.
  • To benefit the land by having nutrients from the decomposing matter seep through the earth and benefit the surrounding areas of the trench. This feeds the land, animals, insects, microbes
  • To give back much needed organic matter and nutrients to the earth in order to aid the soil to recover and encourage intelligent living creatures to flourish
  • To begin giving back to a property and doing all we can to rehabilitate it after taking so much from the land over many years.
  • To gain education and training on large scale land rehabilitation, including planning, designing and implementation
  • Because there was excitement and motivation for the ideas and we wanted to be part of giving it a go.

Lower trench. Drone photo courtesy of Legor Productions

What Was Done:

  • Planning, designing & marking out large scale holes and trenches on damaged areas of properties. Choosing areas that have already been damaged and or will have the the greatest benefit to the most amount of area**.
  • Building large scale trenches and holes, one smaller swale and a previous trench filled. 4 were completed in total on two properties.
  • Fill trenches and holes with organic matter that can decompose and leach nutrients and create healthy soil and ‘feed’ the lower parts of the properties.

Below are basic drawings of depth, dimensions and levels for doing a contour trench on a hill. The principles apply to any trench: keep the base both sideways and longways level  so that water disperses evenly along the entire trench rather than one end or one side only. Ensure the top of the banks (swale humps) are level – see diagram 3. You want the base of the trenches and the banks level, so that moisture will be evenly dispersed over the greatest amount of area.

It is important to take into consideration where the trench is going to seep the most. You want to ensure that the seepage reaches the biggest area possible, or the targeted area.

Widths, lengths and details can be modified.

20170711 Trenches diagram 1

20170711 Trenches diagram 2


20170711 Trenches diagram 3


Dimensions of the Trenches:

Dimensions are dependent on the area that you are digging the trenches.

At the top of a hill it would be dependent on the diameter. If it was very steep you may run a trench along the contour of the land around the hill rather than doing a bowl shape at the top. This would be dependent on the terrain you are working with.

For the ones we were involved with they were dug either along the contour of the land, or on the highest points of the properties. Some were on flatter ground and some were part way down the slope of the hill. The approximate dimensions were as follows:

  • 1.8 metres deep
  • 20-35 plus, metres long
  • At least 3 metres wide some were 10 metres or more

Drone photo courtesy of Legor Productions

Where The Trenches Were Dug:

The trenches were dug at the highest points on the property in order that everything below will benefit.

If the land had been flatter the highest point would have been chosen, or a number of trenches/holes possibly dug on flat ground (site specific decisions would be made).

If the land was really hilly, it would make sense to put the trenches or holes at the very top of the hill/s in a bowl shape so the goodness (nutrients & moisture) would soak out evenly on all sides of the hill and benefit everything below it.



Ingredients Used in the Trenches & Holes

Ingredients To dig:

  • Excavator
  • Level – to ensure the bottom (long ways & sideways) of the trenches and holes is level. To ensure the banks are level.
  • Humans – to drive the vehicles, check the levels, direct the matter




Ingredients To Fill & Cover:

  • Hardwood chip + transport
  • Debosia + Transport
  • Tipper – to move earth, hardwood chip & debosia (a type of local native softwood, a bi-product of an oil extraction process)
  • Natural organic matter including by not limited to: cardboard, green waste, dead trees, tree stumps, felled trees cut up, cactus, anything that will break down but is non-toxic.
  • Loader – to move earth, hardwood chip & debosia
  • Water + transport (or as a gift from God, Rain)
  • Tipper – to move earth, hardwood chip & debosia
  • Loader – to move earth, hardwood chip & debosia
  • Humans – to direct & organise the matter

* As well as filling the trenches, it is also important to cover the banks and any areas that have been damaged or denuded in the process. You will need to take into consideration how much organic matter you need in order to both fill the trenches/holes and to cover the banks and any damage done creating the trenches and holes (example: exposed soil, or where the excavator has left track marks, trucks have dug up soil  when delivering matter etc).

Soil left uncovered and open to the elements with no ground cover dries out rapidly, blows away and can cause erosion quite easily.

The soil on these properties becomes like dust and blows away in the wind. We want to keep as much soil as possible in place and to do so we need to cover it with mulch rather than leave it open to the elements.



Ingredients Required For Documentation:

  • Video Camera
  • Stills Camera
  • Sound Recorder
  • Humans to manage the equipment & write up the data



Method to Create a Trench or Hole:

  • Plan and design the trenches and holes in a  property specific manner. Design the trenches to suit the landscape. We chose the most damaged areas (already cleared) and the areas that would create the most benefit (down hill) for the property.
  • Dig the trenches and holes with excavator
  • Ensure the bottom of the trenches and the banks are Level as you go
  • Create a bank around the edges, or on the lower side of a hill if dug on contour, ensure this is level all round, or with the up hill side of the trench. If you do not make it level when it fills with water you will either have an overflow effect or you will end up with the top of the bank really dry. Remember you want to have as much moisture spreading as evenly as possible in the greatest possible area, or the specific area required.
  • On the lower side of the hill a bank was created, made level and then another trench was dug out to ground level (see diagram 3 below), this was also made level so that there is a deep trench and a less deep trench both that will benefit from the moisture seepage. A lot of earth came out of the trench and it made a very wide bank. Jesus suggested the second trench so that any future planting will benefit from the moisture. If we were to plant on top of the bank without the second, smaller, trench the trees will always be struggling for water, by having the second trench dug to ground level and filled with matter it benefits anything growing on the bank.

20170711 Trenches diagram 3


  • Fill Trenches as soon as possible after trenches have been dug. It is good to have the matter pre-ordered and to arrive as soon as possible after trench/hole completion, leaving earth exposed is not recommended.
  • Put in a ramp for animals so they don’t get stuck in the trench/hole if they accidentally fall in
  • Ensure that all work is done safely. Great care needs to be taken with the loader initially filling the holes and trenches. This is so the loader does not get stuck or fall into the trench. Watch out for power lines and potential hazards, always have a spotter and have at least two, or a team of people, working on dangerous jobs to watch out for each other.
  • Collect or Have fill ingredients delivered (matter)
  • Begin filling
  • If you consider the requirements before digging a trench, you can make it such a way that you can literally back the trucks into the trenches and drop the matter where you want it.
  • Cover all exposed earth and ground with matter (hardwood chip is ideal)
  • Fill with water – preferably by a large rain event, you can wait for this to happen. We are going to truck in some water to the trenches to speed up the process and fill them with water so they can begin decomposition much faster.


  • It is preferable to encourage decomposition rather than composting, this is due to wanting intelligent life to live, flourish and ‘do their thing’. So if you compost it gets too hot and kills everything. Example if you have a heap of green waste it would be better to create thinner layers, this creates less heat
  • If composting is intended to break down or prevent weeds or seeds germinating this can be put at the very bottom of the trench.
  • We have yet to experience for ourselves, but we suspect that the trenches will do a combination of composting and decomposition. Keep this in mind when creating trenches and holes.
  • Hardwood chip if layered too thickly can ignite. Ensure your trenches have enough moisture, or are layered to prevent them getting too hot and catching fire.



Layer with the Following Ingredients:

  1. In the trenches we put some cardboard bales, an old chair, old logs & stumps, cut down trees we had cleared. Some prickly pear tree cactus was added in the bottom as an experiment. Prickly pear tree has heaps of moisture in the plant and as it is buried 1.8metres below the surface we don’t think it will sprout, rather it may cook, compost and decompose, leeching all that moist goodness down the hill.
  2. Layer of hardwood chip (fill approximately 1/2 to 3/4 of the trench)
  3. Layer of debosia (fill 1/4 to 2/4 of trench)
  4. Green waste scraps, any other decomposable matter laying around
  5. Fill anything left with hardwood chip (really you can fill it with what ever you have that is organic matter that will break down and is not toxic, you want to ensure it creates life, not destroys more)
  6. Cover the banks, damaged earth and any other areas with hardwood chip
  7. Add water if possible, to speed up decomposition process
  8. Leave to decompose & seep
  9. Wait and see what happens
  10. Document the trenches and holes regularly to share with others what happens, who moves in, what creatures emerge, when you build a lovely big trench with lots of decomposing matter and moisture seepage.

Drone photo courtesy of Legor Productions

Time & Resources Breakdown for Two Trenches:

Excavator hours: 17 hours to dig 2 trenches, sculpt banks and form smaller trenches + mobilisation @ $153.00 per hour incl. gst.

Hardwood chip: 640 Cubic metres of hardwood chip (8 loads, at least to fill 2 trenches) @ approx. $1830 incl. gst (approx. as this depends on the mill it comes from and transport costs).

Debosia: 200 Cubic metres of debosia (10 loads at least for 2 trenches, we would have liked more but the season is over) @ approx. $190.00 incl. gst per 20 cubic metre load – truck & trailer (this depends on the price of debosia + transport and can vary).

Water: 10 truck loads of water (2 trenches), 10 loads for 2 trenches – water itself a gift, and the trucking to be paid for (10,000 litres per load, total of 100,000 litres for two trenches. Details will be added when the water is delivered)

Time so far: Approximately 16 hours or more of loader, tipper & manual labour work to move all the matter into the trenches.

Loader break down: 15-20 mins for each load of debosia. 20-30mins for a load of woodchip – this is varying with the first load taking longer than the subsequent ones.

Supervising the project and laser leveling the trenches 20 hours over two days for one person. We had one person always with the excavator for safety and ensuring levels were level.

This would take A LOT longer if we were doing it manually and moving it ourselves with just arms, legs, forks and wheelbarrows. There is more work to be done in order to totally complete these trenches.

Time unaccounted for: guiding trucks into tricky areas, being onsite for matter delivery, planning and marking out, level measuring time during trench build (level measuring is approx the same as excavator time). Tipper moving piles of unused dirt, relocating dirt to other projects.



You can do these holes and trenches on a small scale. From Jesus’ discoveries he has done both, and has found the big trenches to be really beneficial, but if you only have a tiny area then the trenches and holes can be scaled down.

We have done a trench in town on a 1 acre block. it was 1.8 metres deep, approximately 1.5 metres wide and as wide as the block. It is doing really well with many creatures attracted to it already.


Hardwood chip spreading. Learning the benefits of matter in soil creation

Thank you’s:

We would like to thank Jesus for his enthusiasm, this idea, his time, direction, training and sharing.

We would like to also thank Jesus, again, Pete & Eloisa, Corny, Wayne involved in trench building & filling, Lena, Igor for documentation, Darryl for the gift of water, and thank those who transported matter and dug the trenches. Some of these people were paid and some volunteered their time. We are grateful for all who were involved in this project and helped out in all the different areas!




If you have any questions please contact us through our contact us page, link here. Or go to the menu bar and choose ‘contact us’.

We feel enthusiastic about this project, are happy to share what we have learned and will happily publish answers to any questions asked.

Until next time, happy experimenting!



** Notes & Further Considerations:

The planning of these projects is really important.

Taking into consideration the environment and eco-systems needs to be considered carefully for each project. Very fragile eco-systems would be treated differently to used farmland for instancce. High mountainous terrain, or steep hills and flat or semi undulating areas would all need different considerations.

For some environments terracing may work, other environments cutting into the land would cause more issues and terrible erosion problems so it may be a matter of building up matter, or becoming innovative with the ways things are done.

The aim is to help land recover faster, not create more damage and problems. In all environments the problems need to be weighed up against the benefits. If the issues and damage will be more than the benefits it is best to not do it in that area.

The point of the trenches is to hold water and create nutrient soaks that hydrate and feed the land.


%d bloggers like this: